WO2002047208A1

WO2002047208A1 - Connector

Info

Publication number: WO2002047208A1
Application number: PCT/DE2001/004572
Authority: WO
Inventors: Thomas Guglhör
Original assignee: Ept Gmbh & Co. Kg
Priority date: 2000-12-06
Filing date: 2001-12-05
Publication date: 2002-06-13
Also published as: GB2385722B; US20040077192A1; GB0313635D0; GB2385722A; AU2002229469A1; US7018243B2; GB2385722A9; WO2002047208A9

Abstract

The invention relates to a connector for use in a straight-through connection systems that is suitable for surface mount techniques. The connector comprises an insulating support in which a plurality of solder-hook terminated and contact-terminated chips are inserted. The connector is further characterized in that the chips are spaced apart, thereby producing flow channels through which the heat transfer medium, for example air, can be fed. According to an advantageous alternative or additional embodiment of the invention, a flow chamber is defined in the zone of the through connection that allows flow of the heat transfer medium at a right angle to the plane of the chips. This channel can be produced by cutouts in the insulating sleeve or by suitable spacers.

Description

description

Connectors

The invention relates to an electrical connector according to the

Preamble of claim 1.

Connectors generally serve for the electrical connection between electrical components or electrical circuits. In electronics, circuit boards have become extremely important as circuit carriers. Electrical connectors can be used to create a reliable electrical connection between circuit carriers, which is usually detachable, usually flat circuit boards. The circuit board-side connections of plug connectors are designed in such a way that a safe electrical and mechanical connection between these plug connector connections and the printed circuit board can be established by suitable processing methods. Classic wave soldering technology, surface soldering technology (English-speaking SMT = Surface Mount Technology) and press-fit technology can be mentioned here as processes. In the case of wave soldering processes and press-in technology, the connector connection is inserted into a through-hole. This is known as push-through technology. A via is part of the circuit located on the printed circuit board and consists of a hole in the printed circuit board material covered with conductive material, which is usually made perpendicular to the surface of the printed circuit board.

The wave soldering process guides the circuit board, on which, in addition to other electronic components, usually one or more connectors are also pre-assembled, via a standing wave made of flowing, liquid solder. The solder consists of a tin alloy heated to the melting point. By contacting the underside of the circuit board, from whose vias the solder connections of the plug connectors protrude slightly, the solder is drawn into the through-contact by capillary forces and then by cooling to a mechanically stable and electrically good connection. Surface soldering is a related process, but usually does not use through-plating. Printed circuit boards in surface technology have conductive tracks made of copper, which are part of the circuit board circuit. The ends of such tracks are geometrically designed for surface soldering technology so that a corresponding electronic or electromechanical component, which is designed for surface soldering technology, can overlap with these connection ends with these ends of the tracks. Before the assembly of the surface components, the ends of the conductor tracks are coated with a tough, sticky solder paste by means of a screen printing process, which is capable of mechanically sufficiently fixing the subsequently applied component until the surface soldering process. The solder paste is composed of very small solder balls, which consist of a tin alloy, a sticky additive that ensures adhesion of the surface component to the circuit board up to the soldering process, and other additives which are intended to improve the solderability. Due to the heat supplied to the solder joints during the surface soldering process, the solder paste melts and the subsequent cooling process between the component connection and the conductor track forms a mechanically stable and electrically conductive solder connection. The adhesive and additives that are added to the solder paste evaporate. The heat transfer to the solder joint takes place alternatively in the surface soldering process by various methods, such as by infrared radiation or by convection. The convection soldering process has gained the greatest importance in this area.

The combination of surface soldering technology and wave soldering processes is used for components of larger dimensions or greater weight, such as connectors. For this purpose, in addition to the surface solder connections, the plated-through holes known from the wave soldering process are also introduced into the circuit board for these components. These plated-through holes are coated by the printing process that is customary for surface soldering technology. With a suitable method, the solder paste is not only applied to the plated-through hole, but also pressed into it. After the component has been pre-assembled, both the component solder connection and the solder paste are in the through-hole. The patent specification EP 0 422 785 B1 shows a connector which is constructed from a plurality of washers which carry the electrical contacts in rows and a carrier insulating body. The connections are made using press-fit technology. The document EP 0 638 967 A2 shows a similar design, in which the printed circuit board connections are made using press-fit technology. The US Pat. No. 3,539,974 shows a connector arrangement which is made up of disks made of insulating material and conductive elements integrated into these disks. The connections of this connector are suitable for wave soldering.

The advantage of the construction of the aforementioned connector designs is the high mechanical stability of the connector and the positional accuracy of the solder connections, which is ensured by guiding the solder connection through the jacket of the same through insulating material right up to the solder joint.

However, the connectors just mentioned have significant disadvantages for the surface soldering process. The solutions mentioned do not, or only inadequately, allow a sufficient amount of heat to be brought to the solder joint in the short time available for the surface soldering process.

The invention has for its object to develop a connector according to the type described in the disc design and push-through technology with the property that it is suitable for the surface soldering process.

This object is achieved by a connector with the features of claim 1.

According to the invention, the connector has an insulating carrier part, into which a multiplicity of disks arranged side by side are inserted, in the insulation jacket of which contact elements are embedded. According to the invention, a gap remains between the wafers inserted into the carrier part, which gap is designed in such a way that sufficient heat transport - be it by convection or by - during the surface soldering process Radiation to the soldering point can be formed. In the conventional solutions, the insulation washers are flush with each other, so that the formation of such a heat flow from the environment to the solder joint is practically prevented. The solution according to the invention makes it possible to heat the solder joint, that is to say the plated-through hole, the solder connection and the solder paste during the surface soldering process, to such an extent that the solder paste melts and an entry into the annular gap between the solder connection and plated-through hole also occurs in the short one available during the surface soldering process Time is allowed.

In an advantageous development of the invention, the washers have spacers in the area of the through-plating, so that the contact elements - or more precisely their solder connections - extend freely in the area between the insulation jacket and the electrical circuit. In other words, according to the invention, the insulation jacket of the wafers is released in the area of the via so that there is an open area between the insulation body of the plug connector and the printed circuit board, which normally allows a heat flow of the medium used for heating to orient the wafers. The relative position of the washer is secured with respect to the connector, since the solder connections are accommodated in the plated-through holes. The spacers act as support points for the respective disc and are selected so that the position of the connector with respect to the electrical circuit (printed circuit board) is reproducible.

These spacers can be formed by protrusions of the insulation jacket or by appropriate design of the contact elements. Due to the formation of these spacers and the gap between two adjacent wafers, the solder connections, the plated-through hole and the solder paste contained therein are so easily accessible for heat transfer during the surface soldering process that a reliable soldered connection can be formed without the reproducible positioning of the Connector relative to the circuit board must be dispensed with. The heat conduction in the area of the solder connections can be further improved if the insulation jacket is provided with recesses which extend in sections along the contact elements and partially expose them, so that the sections of the contact elements adjacent to the solder joint can also be heated directly by convection or radiation. In this way, a maximum heat exchange surface is created for transferring the heat introduced from the outside to the solder joint. However, the recesses are chosen so that the mechanical fixing of the contact elements in the insulation jacket is guaranteed at all times. In other words, in this embodiment, the larger heat exchange area of the solder connections increases their solderability, while the mechanical stability of the connector is only insignificantly reduced.

The relative positioning of the plug connection with respect to the electrical circuit can be further improved if the disk is designed with a holding element which can be brought into engagement with a correspondingly designed counterpart on the printed circuit board. This holding element can, for example, be a snap or latching projection on the insulation part, which snaps into a recess of the circuit in a force-locking or positive manner, for example with a press fit. As an alternative or in addition, the holding element can also be provided by a suitable configuration of the solder connections, for example by kinking at least one solder connection.

The holding element additionally stabilizes the position of the connector relative to the printed circuit board during the soldering process and prevents a misalignment which can lead to the finished printed circuit board becoming unusable later. This is particularly advantageous since surface-mounted components are usually preassembled on the circuit board by automatic machines and only then are they fed to the soldering process. In this case, the maximum setting force with which such an automatic machine can place a component on the printed circuit board or in the through-connection is relatively low. The holding elements are then to be designed in such a way that the setting force which they inevitably cause is not higher than the maximum force which the automatic placement machines can usually exert. In a preferred embodiment of the invention, the

Side wall of the disc is formed at least one support surface, which acts as a contact surface for the adjacent disc. In this way, the relative position of the discs to each other and the maintenance of the gap dimension is ensured according to claim 1.

An additional or alternative fixation of the slices in the carrier part is possible in that the slices are inserted in the height direction with a press fit into the carrier part.

The disks according to the invention are preferably produced by overmolding the contact elements in an injection molding process.

The relative position of the disks can be improved by forming a cover.

Other advantageous developments of the invention are the subject of the further subclaims.

Preferred exemplary embodiments of the invention are explained in more detail below with the aid of schematic drawings. Show it:

Figure 1 shows a connector according to the invention in three-dimensional representation;

2 shows the connector fastened on a printed circuit board according to FIG. 1;

FIG. 3 shows a three-dimensional representation of a small disk of the connector from FIG. 1;

FIG. 4 shows a side view of the disk from FIG. 3 and a section through a printed circuit board according to FIG. 2;

FIG. 5 shows the disk from FIG. 4 in the state soldered to the printed circuit board; FIG. 6 shows a further exemplary embodiment of a small disk in the soldered state;

FIG. 7 shows a third exemplary embodiment of a small disk in the soldered state;

Figure 8 shows another embodiment of a connector according to the invention;

Figure 9 is a washer of the connector of Figure 8 in the soldered state;

Figure 10 is a section along the line A-A in Figure 9;

Figure 11 shows an embodiment of a disc with a holding element;

FIG. 12 three-dimensional representations of the connector according to FIG. 8, the disk according to FIG. 11 and a printed circuit board provided therefor;

Figure 13 shows another embodiment of a washer for a connector and

Figures 14 to 16 variants of the embodiment described with reference to Figures 1 to 3.

Figure 1 shows a simplified three-dimensional representation of a connector 1 in push-through technology. This connector 1 has a carrier part 2, in which adjacent slices 4 are arranged. The carrier part 2 has recesses 6, in which the discs 4 are inserted with one end section. According to FIG. 3, each disk 4 has an insulation jacket 8 in which contact elements 10 are embedded. These penetrate the insulation jacket 8 along the plane spanned by it, in the illustration according to FIG. 3 contact tongues 12 designed in the horizontal direction and in the vertical direction protrude below the solder connections 14 at right angles to each other from the insulation jacket 8. The contact connections 12 with the adjacent end section of the insulation jacket 8 are inserted into the recesses 6 of the carrier part 2.

According to FIG. 2, the connector 1, which is formed with a multiplicity of washers 4, is soldered to a printed circuit board 16 which has a multiplicity of plated-through holes 18 into which the soldered connections 14 are immersed (this will become clearer in the following with reference to FIGS. 4 and 5) ) will be explained. The connector 1 and the printed circuit board 16 are designed in such a way that, when assembled, the washers 4 have a predetermined relative position with respect to the printed circuit board surface 20. In this relative position, a gap 22 with the gap width b (FIG. 1) remains between the printed circuit boards. The spacing of the disks 4 from one another in the exemplary embodiment shown in FIGS. 1 to 3 is defined, on the one hand, by the spacing of the recesses 6 in the carrier part 2 and, on the other hand, by lateral support surfaces 24. These support surfaces 24 are each formed, for example, on the side wall of the insulating jacket 8 which is visible in FIG. 3, so that the adjacent side wall of the adjacent pane 4, which is not visible in FIG. 3, bears against this support surface 24. In principle, the support surfaces 24 can also be formed on both sides of the insulation jacket 8, so that the support surface bears against the support surface in the installed state. The support surfaces 24 furthermore act according to FIG. 1 as an insertion stop which limits the depth of insertion of the washers 4 into the recesses 6 of the carrier part 2.

FIG. 4 shows an enlarged side view of the wafer from FIG. 3 and a sectional illustration of the region of the printed circuit board 16 with which the wafer shown is to be soldered. Accordingly, the contact connections 12 and the solder connections 14 are connected by contact tracks 26, which are essentially surrounded by the insulation jacket 8. These contact tracks 26 have no contact with one another.

The through contacts 18 provided with solder paste 28 are formed in the printed circuit board 16. This via is one with conductive

Material 30 thinly coated hole in the circuit board 16. The solder paste 28 consists of very small solder balls, which are mixed with a heat-evaporating sticky material.

According to FIG. 4, two spacers 32, 34 are formed on the insulation jacket 8, between which the solder connections 14 extend. These two spacers 32, 34 form a free cut 36 in the insulation jacket 8, via which areas of the solder connections 14 are exposed. FIG. 5 shows the plate 4 in the state soldered to the printed circuit board 16. The solder paste 28 is melted by the heat supplied by convection and radiation, and the liquid solder is drawn into the via 18 by capillary forces. By cooling, the solder point 38 is created, via which a solder connection 14 is reliably connected mechanically and electrically to the via 18.

According to FIG. 5, the two spacers 32, 34 are seated on the printed circuit board surface 20, so that a space is formed by the cutout 36, through which portions of the solder connections 14 extend freely. In other words, this free cut 36 forms an additional space which, in cooperation with the columns 22, can be used for heat transport. The heat transport along the free cuts 36 takes place perpendicular to the orientation of the wafers 4. The gaps 22 and the free cuts 36 thus ensure optimal heat transport to and from the via 18, so that the soldering point (via 18, solder connection 14, Solder paste 28) to the soldering temperature and also after the soldering a quick hardening of the soldering point is guaranteed.

FIG. 6 shows an exemplary embodiment in which the flow space for the heat transport medium (for example air) is not formed by two spacers 36, 34 formed in one piece with the insulation jacket 8 but by widenings 40, 42 of the solder connections 14. These widenings 40, 42 are designed such that the lower edge of the insulation jacket 8 is again formed at a distance from the printed circuit board surface 20, these widenings 40, 42 resting on the printed circuit board surface 20 via support points 44. These widenings 40, 42 and the bearing surfaces are designed so that the heat transfer medium is unimpeded can penetrate to the solder joint. In the exemplary embodiment shown in FIG. 6, two of the solder connections 14 were made with widenings 40 and 42, respectively. In principle, it may also be sufficient if only one widening 42 or stop 32 is formed on the projecting part of the pane 4.

FIG. 7 shows an alternative embodiment in which the solutions shown in FIGS. 5 and 6 are combined. In other words, in this exemplary embodiment, the space which enables heat transport along the circuit board surface 20 is formed by a spacer 34 and a widening 42, which together ensure that the soldering points are accessible to the heat transport medium. Otherwise, the exemplary embodiment shown in FIG. 7 corresponds to that from FIGS. 5 and 6, so that further explanations are unnecessary.

A further exemplary embodiment of a plug connector 1 is shown in FIG. Like the exemplary embodiments described above, this has a carrier part 2 into which a multiplicity of disks 4 are inserted. The solder connections 14 of the connector 1 are inserted into the plated-through holes 18 of the printed circuit board 16 (see FIG. 9). Just as in the exemplary embodiment described above, a gap 22 with a gap width b is formed between two adjacent wafers 4, which enables an undisturbed flow of the heat transport medium toward the soldering point.

FIG. 9 shows an illustration of a small disk 4 of the connector 1 from FIG. 8, which is soldered to the printed circuit board 16. Accordingly, the wafer 4 - similar to the exemplary embodiment shown in FIG. 5 - has two spacers 32, 34 with which the wafer 4 is seated on the circuit board surface 20 in the soldered state. A free cut 36 is thus formed between the two spacers 32, 34, which enables heat to be transported along the circuit board surface 20. The heat exchange is additionally improved in the exemplary embodiment shown in FIG. 9 in that the insulation jacket 8 is provided with recesses 44 which extend along the contact tracks 26 indicated by dash-dotted lines. As indicated in Figure 9, the recesses 44 are somewhat narrower than the contact tracks, so that only a partial area is exposed. As a result of this measure, the area of the contact tracks 26 adjoining the solder connections 14 is partially exposed, so that they are accessible to the heat transport medium flowing along the gap 22 and the cut-out 36. That is, the partially cut contact tracks 26 increase the heat exchange area and thus improve the heat transfer to the solder joint. The material of the insulation jacket 8 is located between the conductor tracks 26 and covers the edge region of the contact elements 10 over a width k (arrow in FIG. 9), so that they are reliably held in position.

By this determination of the contact elements 10 there is practically no inaccuracy in the positioning of the solder connections 14 with respect to the circuit board 16, so that the preassembly of the connector on the circuit board 16 is simplified. FIG. 10 shows a section along the line A-A, from which the circumferential edges 46 with the dimension k are gripped by the insulation jacket 8 for fixing the position.

Figure 11 shows a variant of the embodiment shown in Figures 8 to 10. Accordingly, a holding element 48 is formed on the spacer 32 of the wafer 4, which contributes to the additional position fixation during the pre-assembly and during the soldering process. According to the enlarged illustration in FIG. 11, the holding element 48 is formed by two fork sections 50, each curved approximately in a V-shape, the two vertices of the fork sections 50 being spaced apart by the dimension Dh. These fork sections 50 are resilient so that they can be moved elastically towards one another.

According to FIG. 12, two holding bores 52 are formed in the printed circuit board 16, the diameter Db of which is selected to be smaller than the dimension Dh. In the illustrated embodiment, only the two outer washers 4 are formed with holding elements 48, so that correspondingly only two holding bores 52 are provided in the printed circuit board 16. When the plug connector 1 is inserted, the two fork sections 50 of each holding section 48 dip into the holding bores 52. The fork sections 50 are elastically moved towards each other until the outer distance the fork sections 50 corresponds to the dimension Db. When inserted further, the fork sections 50 snap behind the lower peripheral edges of the holding bore 52, so that the connector 1 is fixed. The resilient fork sections 50 can be moved towards one another until they contact with their ends 54. In this contact position, a deformation force becomes significantly higher than the spring force of the individual spring elements. Furthermore, the above-described embodiment of the resilient fork sections 50 acts as a safeguard against breakage of the spring elements, since at the point of greatest mechanical tension (in the connection area of the fork sections 50) there is no further one from the point at which the ends 54 make contact elastic deformation results more, as the arc-shaped resilient elements subsequently stretch in length.

Due to the elastic deformation of the fork sections 50 there is a

Contact force between the holding bore 52 and the holding element 48 perpendicular to the axial direction of the bore and thus results in an axial holding force which is large enough to sufficiently fix the connector for the time between preassembly and the hardening of the soldered connection on the printed circuit board and To maintain alignment of the connector 1 relative to the circuit board 16. This exact alignment is a prerequisite for the later functionality of an assembly.

An exemplary embodiment is shown in FIG. 13, in which the position fixation during the pre-assembly and during the hardening of the soldered connection is not formed by additional holding elements 48 as in the previously described exemplary embodiment, but by a relief, for example, the outermost (right in FIG. 13) solder connection 14 is. With such a notch 56, the solder connection 14 is bulged out to one side. When the kinked solder connection 14 is inserted into a via 18, the raised point of the solder connection 14 touches the adjacent side of the via 18 - the solder connection 14 is mechanically stressed because it is bent out to the side. The contact force which the kinked solder connection 14 applies to the plated-through hole 18 in the radial direction is large enough to achieve a holding force acting in the axial direction. testify about which the connector is adequately fixed on the printed circuit board 16 in the time between preassembly and curing of the soldered connection.

FIGS. 14 to 16 show further variants of the connector 1 described above, in which the guidance of the washers 4 is improved.

FIG. 14 shows a variant in which laterally arranged projections 58 are formed on the side surfaces of the insulation jacket 8, by means of which the disks are spaced apart from one another in the installed position. These projections 58 can be injection molded onto the insulation jacket. The slices 4 shown in FIG. 14 further have - similar to the exemplary embodiment shown in FIGS. 11 and 12 - holding elements 48 which, however, are not designed as a fork section, but rather as a closed, approximately elliptical press ring 60. This press ring 60 is immersed in the holding bore 52 when the washers 4 are inserted, the side portions of the press ring 60 being deformed radially inward, so that the washer 4 is fixed in the holding bore 52 with high strength due to overpressure. In this press-in position, the washers 4 are spaced apart from one another by the lateral projections 58 and the support surfaces 24, so that an extremely precise parallel orientation with the gap dimension b is ensured. Due to the closed shape of the holding elements, higher holding forces can be achieved than with the open shape according to FIG. 11, so that the clamping effect is improved.

In the exemplary embodiment shown in FIG. 14, a cover 62 is also molded onto the carrier part 2, which protrudes roof-shaped from the carrier part 2 and covers the slices 4 in sections. Guide grooves 64 are formed in this cover 62, which engage around the adjacent circumferential edges of the insulation jacket 8 of the washers, so that the parallel guidance is further improved.

FIG. 15 shows a variant in which the cover 62 is extended as far as the solution shown in FIG. 14 up to the front end edge of the pane 4 and thus almost completely covers it. For better cooling 62 cooling slots 68 are formed in the cover, which are related to the gaps between two adjacent slices 4 are aligned. This cover 62 also has guide grooves 64 for the washers 4.

FIG. 16 finally shows a simplified variant of the exemplary embodiment shown in FIG. 15, in which the cover 62 is designed without cooling slots 68.

In principle, the lid structures shown in FIGS. 14, 15 and 16 can be used in all of the above-described exemplary embodiments. The cover can be made in one piece with the carrier part 2 or as an additional component.

A plug-in connector is disclosed which is suitable for the surface soldering process. The connector has an insulating carrier part in which a large number of washers with solder and contact connections are inserted. According to the invention, the disks are spaced from one another, so that flow channels for supplying the heat transport medium, for example air, are created. In an advantageous alternative or additional embodiment of the invention, a flow space is formed in the area of the plated-through hole, which allows the heat transport medium to flow perpendicular to the plane of the leaflets. This channel can be formed by a free cutting of the insulation jacket or by suitable spacing elements.

LIST OF REFERENCE NUMBERS

Connectors

support part

piece

recess

insulation jacket

contact element

Contact Termination

Solder

circuit board

via

PCB surface

gap

support surface

contact track

solder paste

coating

spacer

cutout

soldered point

widening

recesses

peripheral edge

retaining elements

fork portion

retaining holes

End of the fork section

Kinkung

head Start

press ring

cover Guide groove front edge cooling slot

Claims

Expectations

1. Plug connector with an insulating carrier part (2) into which a multiplicity of washers (4) arranged side by side are inserted, each of which has contact elements (10) with contact connections (12) and solder connections (14) embedded in sections in an insulation jacket (8) ), the latter being able to be soldered to plated-through holes (18) or conductor tracks of an electrical circuit, for example a printed circuit board (16), characterized in that a gap () between two adjacent wafers (4) in the area of the solder connections (14) 22) is formed.

2. Connector according to claim 1, wherein the washers (4) in the region of the plated-through hole (18) have spacers (32, 34; 40, 42), so that the contact elements (10) are freely between the insulation jacket (8) and the electrical Circuit extend.

3. Connector according to claim 2, wherein the spacers (32, 34; 40, 42) on the insulation jacket (8) or on the contact elements (10) are formed.

4. Connector according to claim 2, wherein the insulation jacket (8) has recesses (44) which extend along the contact elements (10) and expose them in sections.

5. Connector according to claim 4, wherein the recesses (44) are formed such that the peripheral edges of the contact elements (10) are encompassed along a dimension (k).

Connector according to one of the preceding claims, wherein the washer (4) has a holding element (48, 56) that can be brought into engagement with a correspondingly designed counterpart (52, 18) of the electrical circuit.

7. Connector according to claim 6, wherein the holding element is a spring element (50) which engages in a holding bore (52) of the electrical circuit.

8. Connector according to claim 7, wherein the spring element (50) is integrally formed with the insulation jacket (8).

9. Connector according to claim 6, wherein the holding element is a kink (56) of a solder connection (14) which engages non-positively in the associated via (18).

10. Connector according to one of the preceding claims, wherein protruding support surfaces (24) are formed on a side wall of the disc (4), which act as a contact surface for the adjacent disc (4).

11. Connector according to one of the preceding claims, wherein the insulation jacket (8) of the washer is inserted in the height direction with a press fit in the carrier part (2).

12. Connector according to one of the preceding claims, wherein the washers (4) are made by injection molding around the contact elements (10) in the injection molding process.

13. Connector according to one of the preceding claims, with a cover (62) which covers the washers (4) at least in sections.

14. Connector according to claim 13, wherein the cover (62) is fastened to the carrier part (2) and the washers (4) are either covered in sections or are formed with slots (68) which lead to the gaps (22) between the washers (4th ) are aligned.